How do I change the transition speed (effect) Fade? (code below)

Question

It follows code I’m using, it’s worth mentioning that it’s working 100%, I just can’t (and I really want to) change the speed of the Fade effect.

Follows Code:

.carousel-fade .carousel-inner .item {
    -webkit-transition-property: opacity;
    transition-property: opacity;
}
.carousel-fade .carousel-inner .item,
.carousel-fade .carousel-inner .active.left,
.carousel-fade .carousel-inner .active.right {
    opacity: 0;
}
.carousel-fade .carousel-inner .active,
.carousel-fade .carousel-inner .next.left,
.carousel-fade .carousel-inner .prev.right {
    opacity: 1;
}
.carousel-fade .carousel-inner .next,
.carousel-fade .carousel-inner .prev,
.carousel-fade .carousel-inner .active.left,
.carousel-fade .carousel-inner .active.right {
    left: 0;
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
}
.carousel-fade .carousel-control {
    z-index: 2;
}
html,
body,
.carousel,
.carousel-inner,
.item:nth-child(1) {
    background: white;
}
.item:nth-child(2) {
    background: white;
}
.item:nth-child(3) {
    background: white;
}